test for firstCompletedOf

FutureTest.scala

package scala.concurrent

import org.junit.Assert._
import org.junit.Test
import org.junit.runner.RunWith
import org.junit.runners.JUnit4

import scala.tools.testing.AssertUtil._
import scala.util.Try

import java.util.concurrent.CountDownLatch

@RunWith(classOf[JUnit4])
class FutureTest {
  @Test
  def `bug/issues#10513 firstCompletedOf must not leak references`: Unit = {
    import ExecutionContext.Implicits._
    val unfulfilled = Promise[AnyRef]
    val quick = Promise[AnyRef]
    val result = new AnyRef
    val first = Future.firstCompletedOf(List(quick.future, unfulfilled.future))
    assertNotReachable(result, unfulfilled) {
      quick.complete(Try(result))
    }

    /* The test has this structure:
    val p = Promise[String]
    val q = Promise[String]
    val res = Promise[String]
    val s = "hi"
    p.future.onComplete(t => res.complete(t))
    q.future.onComplete(t => res.complete(t))
    assertNotReachable(s, q) {
      p.complete(Try(s))
    }
    */
  }
}

Interesting, I wasn't aware of this testing style, I most definitely like it better than guessing when's the jvm's going to break...